The proliferation of travel-related web sites providing information and booking services has given customers greater control over travel planning. Such web sites offer easy access to information about destinations, hotels, transportation, activities, and events. In addition, many travel-related web sites offer consumers the opportunity to make travel arrangements online without having to involve a travel agent or other booking agent. In the airline industry, for example, consumers are able to easily search for flights on specified travel dates and, as a result, to obtain a list of available flights and/or available itineraries. Typically, however, the flexibility of the search capabilities is limited to a relatively small set of search criteria. Many web-based search engines in the airline industry allow consumers to search by date and even by time. Some airline industry search engines also allow consumers to sort search results by total travel time, number of connections, or fare. The Travelocity.com web site also offers the capability to select from a list of specific fare classes for different airlines and display a calendar indicating which days the selected fare class on the selected airline is offered.